Obesity is rapidly becoming a major health problem in modern society. It is increasing in prevalence in all developing countries, and in the United States it has reached epidemic proportions. For instance, one in five Americans are obese and one in three are overweight. Of the 67 million overweight and obese Americans, nearly 20 million also have hyperlipidemia. Almost one million Americans die annually from cardiovascular disease and the annual-treatment costs for cardiovascular diseases are an estimated $78.6.
An individual is considered obese when his or her body mass index, or BMI (defined as weight in kilograms divided by the square of height in meters) is greater than 30 kg/m2. Compared to individuals of normal weight (BMI between about 20 and 25kg/m2), overweight (BMI between about 25 and 30 kg/m2) and obese individuals have an increased risk of developing diabetes, cardiovascular disease, hyperlipidemia, arthroses, cancer and other chronic diseases.
Poor nutrition is linked to hyperlipidemia, obesity, hypertension and diabetes, which contribute to the development of cardiovascular disease. Hypercholesterolemia is one of the most important diet-related risk factors for coronary heart disease. More than half of the middle-aged men and women in the United States have serum cholesterol values exceeding 200 mg/dl, values that significantly increase their risk for coronary heart disease.
Because weight-loss and weight-management regimens have frequently been ineffective, effective medical interventions to manage weight gain and slow or prevent progression to obesity are needed. Obesity prevention strategies that begin in early childhood are most effective. Food education program that teach the distinction between healthy food rich in fiber and unhealthy processed food with little fiber content at all are also a necessary component of obesity prevention strategies.
Several studies have indicated that fiber-rich foods and fiber supplements have moderate weight reducing effects, and may also improve the lipid profile in overweight and obese individuals. Alfieri et al. (1995) Obes. Res. 3: 54 ; Birketvedt et al. (2000) Acta Medica 43: 129; Birketvedt et al. (2005) Current Topics in Nutraceutical Research 1; Birketvedt et al. (2002) Nutrition 18: 729. Fiber-rich foods and fiber supplements are also important in controlling or preventing hyperlipidemia. Untreated hyperlipidemia prematurely ages the body's arteries and can lead to stroke, heart attack and kidney failure. Identifying which fiber most effectively controls or prevents hyperlipidemia has been the goal of several studies. Glore et al. (1994) J. Am. Diet. Assoc. 425: 94; Liu et al. (2003) Am. J. Clin. Nutr. 78: 920; Slavin (1987) J. Am. Diet. Assoc.87: 1164; Hillmann et al. (1985) Am. J. Clin. Nutr. 42: 207.
Diets high in fiber content have frequently been used to obtain stable energy intake and avoid metabolic disorders caused by obesity. Scheen (2004) Minerva Endocrinol. 29(2): 31-45; Krotkiewski (1984) Br. J. Nutr. 52(1): 97. These diets also have many other health benefits, such as preventing constipation, hemorrhoids and diverticular disease as well as protecting against colon cancer. Population studies have shown that societies eating a high fiber diet have few obese individuals, while those eating a high fat, low fiber diet have many morbidly obese individuals. Bennet et al. (1996) Postgrad. Med. 99: 153-6, 166-8, and 171.
A study of 203 healthy men showed that men with higher BMI ate more dietary fat and more simple carbohydrates than men with lower BMI. Nelson et al. (1996) J. Am. Diet. Assoc. 96: 771. Consequently, the heaviest men ate fewer complex carbohydrates and less fiber in their diets. Several other studies have supported the proposition that weight gain is inversely associated with the intake of high fiber, whole-grain foods, but directly proportional to the intake of refined-grain foods. Burley et al. (1989) Int. Jou. Obe. 16: 53; Levine et al. (1989) Am. J. Clin. Nutr. 50: 1404. These studies indicate the importance of distinguishing whole-grain products from refined-grain products to aid in weight control, hyperlipidemia and cardiovascular disease.
Dietary is another common method used in weight-loss and weight-management regimens. There are numerous publicly-known diets. Several studies have shown that intensive nutrition intervention with diets rich in dietary fiber can lower serum cholesterol concentration by 20-30%, which may decrease the risk of coronary heart disease. Several studies have also suggested combining dietary fiber with a low fat cholesterol diet, as recommended by the American Heart Association. Brown et al. (1999) Am. J. Clin. Nutr. 69(1): 30; Wolk et al. (1998, 1999) J. Am. Med. Assoc. 2: 281. Dieting, however, is not always successful, and many people fail to lose weight or improve their blood lipid levels. Glore et al., (1994) J. Am. Diet. Assoc. 425: 94.
In spite of all the diets that have been proposed over the years to improve health, many people still face the problem of decreased energy output and increased energy intake. The basic failure in finding the correct balance between energy intake and energy expenditure has resulted in increased obesity and BMI. Replacing processed foods with foods rich in fiber and complex carbohydrates is a preferred solution.
Pharmaceutical approaches to weight control have had mixed results. These products, mostly appetite suppressants, have several serious side effects and health consequences. Consequently, appetite suppressants are not a preferred choice. Other pharmaceutical agents interfere with the body's energy-regulatory mechanisms and may have serious negative effects on the central nervous system through neuroendocrine mechanisms. Another or additional weight-control or weight-reduction approach is to reduce the digestion of starch and the resultant production and absorption of simple sugars. Inhibiting the digestion of starch reduces carbohydrate absorption. The effective inhibition of starch breakdown and the resultant production of simple sugars that alter plasma lipid profiles and promote weight gain, has important implications in the field of weight loss. Phaseolamin, a glycoprotein found mainly in white and red kidney beans, is a known amylase inhibitor the main responsible for the breakdown or digestion of starch. The digestion of starch, which is the main source of carbohydrates in the human diet, begins when food is chewed and mixed with saliva containing α-amylase that randomly hydrolyzes the α(1-4) glycosidic bonds of starch. Because α-amylase cannot cleave the terminal glucosidic bonds and branch points of starch, digestion in the mouth is incomplete. The average chain length, however, is generally reduced from several thousand to less than eight glucose units.
Commercially-available crude bean amylase inhibitors have failed to influence fecal caloric excretion. In addition, many of these commercially available amylase inhibitors cause side effects, such as diarrhea and abdominal discomfort. However, one long term published randomized placebo-controlled study has shown that only minor side effects occurred after intake of a supplement (Wellex) consisting of northern white kidney bean (150 mg) missed with an extract of locust bean gum (25 mg). The same supplement also showed an increased secretion of fat in feces measured in four subjects. Birketvedt et al (2002) Nutrition 18: 729.
In a long term study, the use of the white kidney bean extract mixed with extract of locust bean gum has been shown to have lipid controlling effects. Birketvedt et al. (2002) Nutrition 18: 729.